Listen to Robert Emmerich introduce The Big Apple, a hit song from 1937. Music written by Bob and performed by Tommy Dorsey's Clambake Seven with Bob on piano. Lyrics written by Buddy Bernier and sung by Edythe Wright. Audio provided by Dorothy Emmerich.

French fried onion rings are said to have been invented at Texas’ Pig Stand restaurants (the first “drive ins") in the 1920s. However, “French fried onions” are cited from at least 1908, and Fannie M. Farmer published a “fried onions” recipe in the 1900s.

Wikipedia: Onion RingsOnion rings are a type of fast food commonly found in the United States, Canada, and other places. Pig Stand restaurants claim credit for inventing the onion ring in the 1920s. However other sources state that the onion ring was developed in 1955, when Sam Quigley began the process of perfecting his recipes for hand cut and hand breaded onion rings and sold a limited number of them out of his Nebraska storefront.

Onion rings are cut onions that are sliced to present a ring profile (after punching out each layer of the disc) which are battered and deep fried.

(Oxford English Dictionary)
onion ring, a circular segment of an onion; such a segment deep-fried in batter.
1936 Restaurant Management June 412 French *onion rings.

13 January 1910, Middletown (NY) Daily Times, pg. 4, col. 4:
French Fried Onions.
French Fried onions are more trouble to prepare than fried onions in “American style,” but are not so greasy. Slice the onions, cover them with milk and let them stand for a few minutes; then dip them in flour and fry them in deep fat for eight minutes. Lift them out and drain off the grease by placing them on rough brown paper. Arrange them around the steak and garnish with parsley. The onions may be fried before the meat is broiled, and placed in the oven to keep hot. This will allow plenty of time for draining, and the cook will not have the burden of frying and broiling at the same time.

29 May 1910, New York Sun (New York Public Library’s Susan Dwight Bliss collection, pg. 195):
A novelty that progressive New York restaurants are introducing with great appreciation from their patrons is one that can be reproduced at home without difficulty—French fried onions. In flavor and appearance they bear little relation to the usual breakfast dish, and which, moreover, are possible to many to whom “for the stomach’s sake” the others are impossible. The sweet Bermuda onion is used for this new dainty. It is cut thin to resemble French fried potatoes. Before cooking dredge with flour. Fry quickly in a wire basket in hot deep fat until crisp, brown, and free of grease. Very
delicious as an accompaniment for beef steak, or, in fact, good with almost any kind of red meat.

Feeding AmericaGood Things to Eat
by Rufus Estes
Chicago: The Author
1911
Pg. 63:
FRIED ONIONS—Peel and slice into even rounds four medium-sized onions. Place them first in milk then in flour, fry in very hot fat for eight minutes. Remove them carefully and lay on a cloth to dry. Place a folded napkin on a dish, lay the onions on, and serve very hot. Garnish with fried parsley.

11 August 1917, Ogden (Utah) Standard, pg. 5, col. 3:
Cut the onions into thin rings, melt the margarine in a saucepan, put in the onion rings and cook, without browning, for five minutes. Remove them from the pan and add the corn flour, blending it well with the butter; add gradually the cold milk or stock; mix well, bring to the boil, put in the onions and simmer until tender.

21 December 1923, Davenport (Iowa) Democrat and Leader, pg. 16, col. 6:
A single glazed onion, with a top-knot of parsley, is a favorite garnish in the onion-loving family; while fried onion rings will be sure of welcome.

29 October 1930, Manitoba (Winnipeg) Free Press, pg. 18, col. 6-7:
FRENCH FRIED ONIONS
Peel the onions and cut them in slices across to form circles when the slices are separated. Cook by any of the following methods:

Method No. 1—Place in frying basket and fry in deep hot fat, shaking the basket constantly while the onions are cooking. Fry to a golden brown and drain on unglazed papers and serve with steak or fish.

Method No. 2—Dip the onion rings in milk, drain and dip in flour and proceed as above in Method No. 1. Sprinkle with salt when done.

Method No. 3—Peel onions and slice one-eighth inch across and soak in cold milk for one hour. Drain and dip in fritter batter, fry in deep hot fat but do not use the wire basket as they will stick to it. Fry until a delicate brown and slightly puffed. Drain on unglazed paper.

Batter for Method No. 3—One cupful flour, one-third teaspoonful salt, two-thirds cupful water, six teaspoonfuls olive oil or melted fat and one well beaten egg white. After sifting the dry ingredients together add the water, then beat for a few minutes until smooth. Add oil and beat one minute. Fold in egg white, and use immediately.

5 January 1937, New York Herald Tribune, pg. 10, col. 7:
ONION RINGS—French fried onion rings, sweet and crisp, are selling in small bags for ten cents. Nothing offers more honest delight for a cocktail munch tray. Or heat them for a moment and serve over a thick broiled steak. No bother and they taste like the French chef kind, dipped, crisp and glistening from a kettle of hot fat.